Which of the following quasars would you expect to have the largest number of hydrogen absorption lines in its spectrum? 

How far is the Virgo cluster from our Galaxy? 

Why do disk stars bob up and down as they orbit the galaxy? 

What

is the typical percentage (by mass) of elements other than hydrogen and

helium in stars that are forming right now in the vicinity of the Sun?

How might two colliding spiral galaxies tend to create an elliptical galaxy? 

Which kind of object is the best standard candle for measuring distances to extremely distant galaxies? 

What products are formed as an immediate result of the fusion of two protons in p-p chain reaction? 

The fact that we observe neutrinos from the Sun provides direct evidence of 

At the centre of the Sun, fusion converts hydrogen into 

What causes the cycle of solar activity?